Embodiments of the present invention relate to a substrate for liquid crystal display, a manufacturing method thereof and an assembled panel.
Recently, liquid crystal displays (LCDs) have been widely applied to personal digital assistants (PDAs), play station portables (PSPs), global positioning systems (GPSs) and the like. Among various kinds of liquid crystal displays, thin film transistor liquid crystal displays (TFT-LCDs) have prevailed in the market of flat panel displays due to the advantages of low power consumption and free of radiation and the like.
The display panel of a TFT-LCD comprises a thin film transistor (TFT) array substrate, a color filter substrate, and a liquid crystal layer interposed therebetween. The principle based on which a TFT-LCD displays an image is that the liquid crystal molecules in the liquid crystal layer can be rotated with the intensity of the electric field applied thereon by the voltage applied from the driving circuit and accordingly the alignment direction of the liquid crystal molecules are changed so that the amount of light transmitted through the liquid crystal layer is changed.
A conventional process of manufacturing a TFT-LCD panel generally comprises a TFT process, a color filter process, a cell process and a module process. The cell process can comprise four steps as follows: applying an alignment film and curing the alignment film on the surfaces of a TFT array substrate and a color filter substrate; rubbing the alignment films and forming grooves along a certain direction on the surfaces of the alignment films so that liquid crystal molecules can be pre-aligned along the direction; assembling the TFT array substrate and the color filter substrate with a sealant member and curing the sealant member; and performing a cutting process on the assembled substrates to form individual panels.
In assembling, firstly liquid crystal material is dropped and sealant is coated to form a sealant member comprising a subsidiary sealant member and a primary sealant member, and then the TFT array substrate and the color filter substrate are bonded together. As shown in FIG. 1, a plurality of individual panels 14 are obtained after assembling the TFT array substrate and the color filter substrate. The individual panel 14 comprises an individual panel region of the TFT array substrate, an individual panel region of the color filter substrate, and a liquid crystal layer held between the two individual panel regions.
The individual panel regions of the TFT array substrate and the individual panel regions of the color filter substrate face each other and are equal in number. During the assembling process, liquid crystal material is firstly dropped onto the individual panel regions of the TFT array substrate or the individual panel regions of the color filter substrate, the primary sealant is applied along the edges of the individual panel regions of the TFT array substrate or the color filter substrate, which has not the liquid crystal material dropped thereon, the subsidiary sealant is applied on the periphery of the individual panel regions, and then the TFT array substrate and the color filter substrate are bonded together and the sealants are cured through light irradiation or thermal treatment.
As shown in FIG. 2, gate lines, data lines, thin film transistors 7 and other components are provided in the individual panel regions of the TFT array substrate, and a black matrix 9, a color filter film 8 and other components are provided in the individual panel regions of the color filter substrate.
The panel obtained by assembling the TFT array substrate and the color filter substrate is cut into a plurality of individual liquid crystal display panels.
Because the space between the TFT array substrate and the color filter substrate is vacuumed when the TFT array substrate is bonded with the color filter substrate under a vacuum situation and pressure in the space is quite low, the primary sealant member 2 may be easily attacked by the airflow entering into the regions between the subsidiary sealant member 15 and the primary sealant member 2 through the opening regions 12 of the subsidiary sealant member 15 after the panel is exposed to the atmosphere. Therefore, the primary sealant member 2 is damaged or broken and the display quality can be degraded due to the produced bubbles.